Brush assembly



Feb. 25, 1936. H, DUNHAM .l 2,032,084

BRUSH ASSEMBLY Filed Deo. 24, 1954 2, Sheets-Sheet 1 25 Wr ff $0 Z n Z0 Fg o o I7 \T l, H. DUNHAM BRUSH ASSEMBLY 2 Sheets-Sheet 2 Filed DeG. 24, 1934 Patented Feb. 25, 1936 UNITED STATES PATENT oFFioE tric Motor Corporation, Racine, Wis.,

ration oi' Wisconsin Application December 24, 1934, Serial No. 759,084

4 Claims.

This invention appertains to electric motors, and more particularly to a novel brush assembly therefor.

In certain lines of the electric motor industry,

5 it is essential that the motors be so constructed that the same can be economically manufacured on a quantity basis and still be of a rugged and durable type capable of withstanding the hard usage of the layman.

invention to provide novel means for simplifying the brush assembly of electric motors, whereby the samecan be cheaply made and readily assembled in the motor casing, and capable of effectively performing its desired ofiice, the construction being such that the brushes can be easily renewed when worn. Y

Another important object of my invention is the provision of novel and effective means for as insuring the proper contact between the brush and its holder or housing on motors both o1' the high and low amperage type.

further object of my invention is the provision ci novel means for constructing the housing or holder and the contact member of brushes of the shunt type, used with current or high amperage, in which not only the proper contact is insured without deterring from the function of the brush spring, but ease in assembling is also obtained.

A further object of my invention is the provision of an insulation plate for each brush assembly, with novel means for connecting the onepiece sheet metal brush holder or housing there- 35 with, and with novel means for anchoring or securing the plate to the motor casing,A whereby a simple construction is obtained with the desired spacing between the motor casing and the current conducting parts of the brush assembly.

A still further object of my invention is the provision of adjustable caps carried by the motor casing, and independent of thebrush holder, for securing the desired adjustment of the brush spring and the proper Contact between the spring and the housing, the caps allowing the removal of the spring and brush through the casing.

With these and other objects in View, the invention consists in the novel construction, ar- 5@ rangement,v and formation of parts, as Will be hereinafter more speciilcally described, claimed, and illustrated in the accompanying drawings, in which drawingsz- Figure 1 is an inner end elevation of a part of a motor casing, showing one form of my improved Cil It is therefore one of the salient objects of my brush assembly incorporated therewith, parts of one of the brush assemblies being shown broken away and in section to illustrate structural detalls.

Figure 2 is an enlarged fragmentary section teiten substantially on the line 2--2 of Figure l, locking in the direction of the arrows.

Figure 3 is a detail fragmentary section, taken on the line 3 3 or" Figure l, looking in the direction of the arrows, illustrating the means for anchoring or securing the brush housing or holder to the motor casing. l Figure 4 is a transverse section through the brush assembly taken substantially on the line 4 4 of Figure 2, looking in the direction of the arrows, illustrating the means of anchoring 'the assembly to the .motor casing.

Figure 5 is a. detail transverse section taken substantially on the line 5--5 of Figure 2, illus trating the brush spring contact ring.

Figure 6 is a view similar to Figure l, iiiustratlng another form of brush assembly.

Figure '7 ls an enlarged fragmentary sectional View taken substantially on the line lul of Figure 5.

Figure 8 is a detail plan view of the blank from which the brush holder or housing is formed.

Figure 9 is a detail side elevation of the brush holder support.

Figure 10 is a detail side elevation of my novel Contact clip.

Figure l1 is a detail plan vien7 of the brush holder base or plate.

Referring to the drawings in detail, wherein similar reference characters designate correspending parts throughout the several views, 'tite letter C generally indicates one part of a motor casing, and the letter A one form of my improved brush assembly associated therewith.

The motor casing part C includes an annular side wall l5, and an end wall i8, through which extends the armature shaft (not shown) which carries the usual commutator and armature core. The casing part C is detachably associated with the main part (not shown) of the motor casing.

My improved brush assembly A comprises a brush holder base or plate 20 formed of insulation, and the same is provided at spaced points on opposite sides of its longitudinal axis with slots 2 l ,for a purpose which will be later set forth. This plate of insulation is also provided with slots 22 adjacent to the side edges of the plate, and the purpose of these slots will be more fully set forth.

Flrmly mounted upon the plate or base 2D is the brush holder or housing 23, which is formed from a single blank of sheet metal 24 iolded on longitudinal lines 25 to provide spaced, longitudinally extending side wallsI 26 and an outer connecting wall 2. The side walls 26 have formed thereon bendable tongues 28, which are inserted through the slots 2 i, and then clinched, as clearly shown in Figure 4 of the drawings. By this arrangement a brush holder or housing is formed open at its opposite ends.

To securely anchor the plate or base 2@ with the housing 23 to the motor casing part C, I utilize a pair of sheet metal brush holder supports or clips 29. The inner longitudinal edges of the clips 29, vor brush holder supports, are each provided with a tongue 3i, and these tongues are inserted through the slots 22 and then upset as at 3i. with a pair of spaced legs 32, which arel inserted through slots 33 formed in the motor casing part C, and after these legs are inserted in place, the same' are bent at right angles, as at 3d, into intimate contact with lthe outer face of the motor casing part C. By this arrangement of parts it can be seen that a simple brush holder is provided with exceptionally simple and durable means for anchoring the same to the motor casing with the proper and desired spacing.

In the shunt type of brush holder, one longitudinal side wall 28 of the brush housing or holder is provided with a longitudinally ex` tending slot 35, which terminates short of the inner end of the housing. The opposite end of the slot 35 opens out through the outer end of the housing. r'he housing slidably receives the .brush 36, which has lrmly anchored to its inner end the Wire 3l?, which Wire has in turn anchored thereto the current conducting contact ring 33. The wire 3l slidably extends thrugh the slot 35 so that free, uniinpeded sliding movement of the Ibrush Se is insured. Mounted within the inner 'into intimate engagement with the housing or brush support 23. I lay particular stress on the contact ring 33, as by the use of the same free movement of the spring 3Q is insured, and at the same time I am permitted to obtain a positive contact between the ring and the housing or sup port 23.

Referring more particularly to Figures (i, 3, and i6, it will be seen that I have shown a brush assembly of the low an'iperage type, and this hrush assembly is identical with the brush assenihiy just described, with the exception that a contact clip ii is utilized instead oi the contact ring In .torni I also employ a brush thin which ti e They outer edges of the clips are provided wire 81 is ated, and hence the necessity of the slot te is also dispensed with.

Particular attention is invited to the contact clip ii, and it will be noted that the same includes a hollow circular body portion d3, which is detachably tted within the insulated cap 40. Formed on the hollow head 43V are resilient diverging legs dit. In assembling the brush parts in this form, the expansion brush spring is placed within the brush holder or housing against the brush, and in the hollow head Q3, and the legs of the clip are placed on opposite sides of the brush holder or housing in intimate engagement with the side walls thereof. Obviously, upon tightening of the cap the legs will be forced into tighter engagement with the brush holder or housing, thus insuring proper contact between the spring and the housing.

Changes in details may be made without de-s parting from the spirit or scope of this invention, but what I claim as new is:-

1. In an electric motor, e. casing, and a brush assembly therefor including a brush holder, the casing having an opening in alinement with the holder, a cap of insulation adjustably threaded in the opening and movable toward and away from the holder, an expansion spring having its opposite ends fitted within the holder and the `cap, and a contact clip carried by the cap and receiving the spring having resilient legs movable into intimate contact with the sides of the holder by said cap.

2. In an electric motor, a casing having an opening therein/and la brush assembly therefor including a brush holder in alinement with the opening, a brush slidably mounted in said holder, a hollow cap of insulation adjustably threaded into said opening, a contact clip including a hollow head tted withinthe cap, and resilient contact legs for engaging the opposite sides of the holder, and an expansion spring iitted within the holder and in the hollow head.

3. As a new article of manufacture, a contact clip for brush assemblies comprising a hollow head and a pair of spaced resilientlegs formed on said head and diverging therefrom.

d. In an electric motor, 'a casing, a brush assembly disposed within the casing, including a plate formed of insulation having a pair of spaced slots on opposite sides of its longitudinal axis, and another pair ,of slots adjacent 'to its side edges, a support' including a pair of metallic plates having tongues insertable through the slots adjacent to the side edges of the plate and bendable tongues for engaging the motor casing whereby to hold the platein spaced relation tothe motor casing, a one-piece sheet metal housing including side walls and a connecting wall, bendable tongues on the side walls insertable through the .tust-mentioned slots or the plate, whereby to anchor the housing to the plate, and a brush siidabiy mounted in the housing on the plate.

mimi'. H. DUNHAM. 

